Insulating target material, method of manufacturing insulating target material, conductive complex oxide film, and device

ABSTRACT

An insulating target material for obtaining a conductive complex oxide film represented by a general formula ABO 3 , the insulating target material including an oxide of an element A, an oxide of an element B, and at least one of an Si compound and a Ge compound.

Japanese Patent Application No. 2005-235809, filed on Aug. 16, 2005, ishereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

The present invention relates to an insulating target material suitablyused for radio frequency (RF) sputtering, a method of manufacturing theinsulating target material, a conductive complex oxide film, and adevice.

A target for obtaining a complex oxide film by sputtering is generallyobtained as follows. For example, a target for obtaining a perovskiteoxide film of the general formula ABO₃ is obtained by pulverizing oxideraw materials of the element A and the element B, mixing the oxide rawmaterials taking the stoichiometric composition into consideration, andsintering the mixture. A material disclosed in JP-A-10-176264 has beenknown as such a target, for example. This document discloses asputtering target for a perovskite oxide of the chemical formula ABO₃which has a specific relative density and size.

On the other hand, the inventor of the invention found that a targetsufficient for obtaining a conductive complex oxide film of the generalformula ABO₃ cannot be obtained by merely pulverizing oxide rawmaterials of the element A and the element B and mixing and sinteringthe oxide raw materials at a specific composition.

For example, the inventor formed a target for forming an LaNiO₃conductive complex oxide film by RF sputtering using a known sinteringmethod to obtain the following findings. Specifically, a target obtainedby mixing an La oxide powder and an Ni oxide powder at a compositionratio of 1:1 and sintering the mixture did not exhibit uniforminsulating properties over the entire target, in which a portionexhibiting low insulating properties (i.e. portion exhibitingconductivity higher than that of the surrounding portion) was formed.When RF sputtering is performed using such a target, plasma isconcentrated on the portion exhibiting low insulating properties,whereby the portion on which the plasma is concentrated may be dissolvedor cracks may occur in the target due to plasma concentration. Thismakes it difficult to use such a target for RF sputtering.

SUMMARY

According to a first aspect of the invention, there is provided aninsulating target material for obtaining a conductive complex oxide filmrepresented by a general formula ABO₃, the insulating target materialcomprising:

an oxide of an element A;

an oxide of an element B; and

at least one of an Si compound and a Ge compound.

According to a second aspect of the invention, there is provided amethod of manufacturing an insulating target material for obtaining aconductive complex oxide film represented by a general formula ABO₃, themethod comprising:

mixing an oxide of an element A and an oxide of an element B,heat-treating the resulting mixed powder, and pulverizing the resultingproduct to obtain a first powder;

mixing the first powder and a solution including at least one of an Siraw material and a Ge raw material, and collecting the resulting powderto obtain a second powder;

heat-treating the second powder and pulverizing the resulting product toobtain a third powder; and

heat-treating the third powder.

According to a third aspect of the invention, there is provided aconductive omplex oxide film, being formed by RF sputtering method usingthe above-described insulating target material.

According to a fourth aspect of the invention, there is provided adevice, comprising:

a base; and

the above-described conductive complex oxide film formed above the base.

According to a fifth aspect of the invention, there is provided aninsulating target material, comprising:

an oxide of a first element;

an oxide of a second element; and

at least one of an Si compound and a Ge compound.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a flowchart showing a method of manufacturing an insulatingtarget material according to one embodiment of the invention.

FIG. 2 is a photograph showing the outward appearance of an insulatingtarget material of Example 1 of the invention.

FIG. 3 is a photograph showing an insulating target material ofComparative Example 1.

FIG. 4 is a view showing heat treatment and evaluation results of aconductive complex oxide film of Example 2 of the invention.

FIG. 5 is a view showing X-ray analysis results of the conductivecomplex oxide film of Example 2.

FIG. 6 is an SEM view of the conductive complex oxide film of Example 2.

FIG. 7 is a photograph showing the outward appearance of the conductivecomplex oxide film of Example 2.

FIG. 8 is a view showing heat treatment and evaluation results of aconductive complex oxide film of Comparative Example 2.

FIG. 9 is a view showing X-ray analysis results of the conductivecomplex oxide film of Comparative Example 2.

FIG. 10 is a view showing X-ray analysis results of the conductivecomplex oxide film of Comparative Example 2.

FIG. 11 is an SEM view of the conductive complex oxide film ofComparative Example 2.

FIG. 12 is a photograph showing the outward appearance of the conductivecomplex oxide film of the comparative example.

FIG. 13 is a view showing heat treatment and evaluation results of aconductive complex oxide film of Example 3 of the invention.

FIG. 14 is a view showing X-ray analysis results of the conductivecomplex oxide films of Example 3 and Comparative Example 4.

FIGS. 15A and 15B are views showing a semiconductor device according toone embodiment of the invention.

FIG. 16 is a cross-sectional view schematically showing a 1T1Cferroelectric memory according to one embodiment of the invention.

FIG. 17 is a view showing an equivalent circuit of the ferroelectricmemory shown in FIG. 16.

FIG. 18 is a cross-sectional view schematically showing a piezoelectricdevice according to an application example of one embodiment of theinvention.

FIG. 19 is a schematic configuration view of an inkjet recording headaccording to an application example of one embodiment of the invention.

FIG. 20 is an exploded perspective view of an inkjet recording headaccording to an application example of one embodiment of the invention.

FIG. 21 is a schematic configuration view of an inkjet printer accordingto an application example of one embodiment of the invention.

FIG. 22 is a cross-sectional view showing a surface acoustic wave deviceaccording to an application example of one embodiment of the invention.

FIG. 23 is a perspective view showing a frequency filter according to anapplication example of one embodiment of the invention.

FIG. 24 is a perspective view showing an oscillator according to anapplication example of one embodiment of the invention.

FIG. 25 is a schematic view showing an example in which an oscillatoraccording to an application example of one embodiment of the inventionis applied to a VCSO.

FIG. 26 is a schematic view showing an example in which an oscillatoraccording to an application example of one embodiment of the inventionis applied to a VCSO.

FIG. 27 is a block diagram showing the basic configuration of a PLLcircuit according to an application example of one embodiment of theinvention.

FIG. 28 is a block diagram showing the configuration of an electroniccircuit according to an application example of one embodiment of theinvention.

FIG. 29 is a view showing a communication system using a reader/writeraccording to an application example of one embodiment of the invention.

FIG. 30 is a schematic block diagram of the communication system shownin FIG. 29.

DETAILED DESCRIPTION OF THE EMBODIMENT

The invention may provide an insulating target material for obtaining aconductive complex oxide film which is uniform and exhibits excellentproperties such as excellent insulating properties.

The invention may also provide a method of manufacturing the aboveinsulating target material.

The invention may also provide a conductive complex oxide film formed byusing the above insulating target material.

The invention may further provide a device including the aboveconductive complex oxide film.

According to one embodiment of the invention, there is provided aninsulating target material for obtaining a conductive complex oxide filmrepresented by a general formula ABO₃, the insulating target materialcomprising:

an oxide of an element A;

an oxide of an element B; and

at least one of an Si compound and a Ge compound.

The insulating target material according to this embodiment may besuitably used for RF sputtering due to uniformity and excellentinsulating properties. The insulating target material according to thisembodiment allows a conductive complex oxide film which exhibitsexcellent crystal orientation and excellent surface morphology to beobtained.

In this insulating target material, the element A may be at least oneelement selected from La, Ca, Sr, Mn, Ba, and Re.

In this insulating target material, the element B may be at least oneelement selected from Ti, V, Sr, Cr, Fe, Co, Ni, Cu, Ru, Ir, Pb, and Nd.

In this insulating target material, the Si compound and the Ge compoundmay be oxides.

The insulating target material may further comprise an Nb compound.

In this insulating target material, the element A may be La, and theelement B may be Ni.

According to one embodiment of the invention, there is provided a methodof manufacturing an insulating target material for obtaining aconductive complex oxide film represented by a general formula ABO₃, themethod comprising:

mixing an oxide of an element A and an oxide of an element B,heat-treating the resulting mixed powder, and pulverizing the resultingproduct to obtain a first powder;

mixing the first powder and a solution including at least one of an Siraw material and a Ge raw material, and collecting the resulting powderto obtain a second powder;

heat-treating the second powder and pulverizing the resulting product toobtain a third powder; and

heat-treating the third powder.

The manufacturing method according to this embodiment allows aninsulating target material which is uniform and exhibits excellentinsulating properties to be obtained.

In this method of manufacturing an insulating target material,

the solution may include at least one of the Si raw material and the Geraw material in an amount of 2 to 10 mol %.

In this method of manufacturing an insulating target material, the mixedpowder may be heat-treated at 900 to 1000° C.

In this method of manufacturing an insulating target material, thesecond powder may be heat-treated at 900 to 1000° C.

In this method of manufacturing an insulating target material, the thirdpowder may be heat-treated at 1000 to 1500° C.

According to one embodiment of the invention, there is provided aconductive complex oxide film, being formed by RF sputtering methodusing the above-described insulating target material.

According to one embodiment of the invention, there is provided adevice, comprising:

a base; and

the above-described conductive complex oxide film formed above the base.

The device according to this embodiment refers to a device including theabove conductive complex oxide film, and includes a part including theconductive complex oxide film and an electronic instrument including thepart. Specific examples of the device are described later.

According to one embodiment of the invention, there is provided aninsulating target material, comprising:

an oxide of a first element;

an oxide of a second element; and

at least one of an Si compound and a Ge compound.

Some embodiments of the invention will be described in detail below.

1. Insulating Target Material

An insulating target material according to one embodiment of theinvention is an insulating target material for obtaining a conductivecomplex oxide film of the general formula ABO₃ and includes an oxide ofan element A (first element), an oxide of an element B (second element),and at least one of an Si compound and a Ge compound.

Specifically, at least the element A and the element B are included inthe insulating target material according to this embodiment as oxides.The element A may be at least one element selected from La, Ca, Sr, Mn,Ba, and Re. The element B may be at least one element selected from Ti,V, Sr, Cr, Fe, Co, Ni, Cu, Ru, Ir, Pb, and Nd.

A uniform insulating target material which exhibits excellent insulatingproperties can be obtained by incorporating at least one of the Sicompound and the Ge compound into the insulating target materialaccording to this embodiment, as is clear from the examples describedlater. It is preferable that the insulating target material include atleast the Si compound of the Si compound and the Ge compound. It ispreferable that the Si compound and the Ge compound be oxides.

In this embodiment, the insulating target material may further includean Nb compound such as an Nb oxide. An oxygen deficiency in thedeposited conductive complex oxide film can be compensated for byincorporating the Nb oxide into the insulating target material.

The oxide of the element A and the oxide of the element B may beincluded in the insulating target material according to this embodimentat the same ratio as the stoichiometric composition of the depositedconductive complex oxide (general formula ABO₃), that is, at a ratio ofA:B=1:1 or a ratio close to this ratio. It is preferable that theinsulating target material according to this embodiment not have aperovskite structure of the general formula ABO₃. When the insulatingtarget material has such a perovskite structure, the resulting targetexhibits conductivity. As a result, the target may not be suitably used,or cannot be used, as a RF sputtering target.

As examples of the conductive complex oxide film to which the insulatingtarget material according to this embodiment may be applied, La(Sr)CoO₃(the metal in the parentheses indicates a substituent metal; hereinafterthe same) such as LaCoO₃, SrCoO₃, and La_(1-x)Sr_(x)CoO₃ (wherein x andy represent rational numbers of 0 to 1; hereinafter the same),La(Sr)MnO₃ such as LaMnO₃, SrMnO₃, and La_(1-x)Sr_(x)MnO₃, LaNiO₃,SrNiO₃, La(Sr)NiO₃, CaCoO₃, La(Sr)(Fe)CoO₃ such as La(Ca)CoO₃, LaFeO₃,SrFeO₃, La(Sr)FeO₃, and La_(1-x)Sr_(x)Co_(1-y)Fe_(y)O₃,La_(1-x)Sr_(x)VO₃, La_(1-x)Ca_(x)FeO₃, LaBaO₃, LaMnO₃, LaCuO₃, LaTiO₃,BaCeO₃, BaTiO₃, BaSnO₃, BaPbO₃, BaPb_(1-x)O₃, CaCrO₃, CaVO₃, CaRuO₃,SrIrO₃, SrFeO₃, SrVO₃, SrRuO₃, Sr(Pt)RuO₃, SrTiO₃, SrReO₃, SrCeO₃,SrCrO₃, BaReO₃, BaPb_(1-x)Bi_(x)O₃, CaTiO₃, CaZrO₃, CaRuO₃,CaTi_(1-x)Al_(x)O₃, and the like can be given.

2. Method of Manufacturing Insulating Target Material

The insulating target material according to one embodiment of theinvention may be formed using the following method. This insulatingtarget material is a target material for obtaining a conductive complexoxide film of the general formula ABO₃.

The manufacturing method according to this embodiment includes mixing anoxide of an element A and an oxide of an element B, heat-treating themixed powder, and pulverizing the resulting product to obtain a firstpowder, mixing the first powder and a solution including at least one ofan Si raw material and a Ge raw material and collecting the resultingpowder to obtain a second powder, heat-treating the second powder andpulverizing the resulting product to obtain a third powder, andheat-treating the third powder.

In more detail, the manufacturing method according to this embodimentmay include the steps shown in FIG. 1.

(1) Production of First Powder

A powder of an oxide of the element A and a powder of an oxide of theelement B are mixed at a composition ratio of 1:1, for example (stepS1). The resulting mixed material is calcined at 900 to 1000° C. andpulverized to obtain a first powder (step S2). The resulting firstpowder includes the oxide of the element A and the oxide of the elementB.

(2) Production of Second Powder

The first powder and a solution including at least one of an Si rawmaterial and a Ge raw material (Si raw material and/or Ge raw material)are mixed (step S3). As the Si raw material or the Ge raw material, analkoxide, organic acid salt, inorganic acid salt, or the like which maybe used as a precursor material for a sol-gel method or an MOD methodmay be used. As the solution, a solution prepared by dissolving the Siraw material and/or the Ge raw material in an organic solvent such as analcohol may be used. The Si raw material and/or the Ge raw material maybe included in the solution in an amount of 2 to 10 mol % of theconductive complex oxide of the general formula ABO₃.

The Si raw material and the Ge raw material are preferably liquid atroom temperature or soluble in the solvent. As examples of the compoundwhich may be used, an organic salt, alkoxide, inorganic salt, and thelike can be given. As specific examples of the organic salt, formate,acetate, propionate, butyrate, octylate, stearate, and the like of Siand Ge can be given. As specific examples of the alkoxide, ethoxide,propoxide, butoxide, and the like of Si and Ge can be given. Thealkoxide may be a mixed alkoxide. As specific examples of the inorganicsalt, hydroxide, chloride, fluoride, and the like of Si and Ge can begiven. These compounds may be directly used when these compounds areliquid at room temperature, or may be used after dissolving the compoundin a solvent. The Si raw material and the Ge raw material are notlimited to the above compounds. A number of Si salts and Ge salts otherthan the above compounds may also be suitably used.

The powder and the solution are then separated by filtration or the liketo obtain a second powder (step S4). The resulting second powder isobtained by mixing the first powder and the solution.

(3) Production of Third Powder

The second powder is calcined at 900 to 1000° C. and pulverized toobtain a third powder (step S5). The resulting third powder includes theoxide of the element A, the oxide of the element B, and the oxides ofthe Si raw material and/or the Ge raw material.

(4) Sintering

The third powder is sintered using a known method (step S6). Forexample, the third powder may be placed in a die and sintered by vacuumhot pressing. The third powder may be sintered at 1000 to 1500° C. Theinsulating target material according to this embodiment may be thusobtained.

(5) Grinding

The resulting insulating target material may be ground on the surface bywet grinding, as required.

The manufacturing method according to this embodiment allows a uniforminsulating target material exhibiting excellent insulating properties tobe obtained due to inclusion of the step of mixing the first powder andthe solution of the Si raw material and/or the Ge raw material, as isclear from the examples described later. According to this manufacturingmethod, an insulating target material can be obtained which produces aconductive complex oxide film exhibiting highly controlled crystalorientation and excellent surface morphology.

3. Conductive Complex Oxide Film

A conductive complex oxide film of the general formula ABO₃ may beobtained by RF sputtering using the above insulating target material.The conductive complex oxide film includes at least one of Si and Ge,and preferably at least Si. The conductive complex oxide film of thegeneral formula ABO₃ may include at least one of Si and Ge in an amountof 0.001 to 5 mol %, and preferably 0.001 to 1 mol %. Specific examplesof the conductive complex oxide film of the general formula ABO₃according to this embodiment have been described above. Therefore,further description is omitted.

In RF sputtering, argon and oxygen may be used as the sputtering gas. Inthis embodiment, an excellent conductive complex oxide film may beobtained in an atmosphere which contains only argon and does not containoxygen.

The conductive complex oxide film according to this embodiment exhibitsexcellent crystal orientation and excellent surface morphology. Forexample, it was confirmed that a (100)-oriented LaNiO₃ film can beobtained by RF sputtering when using an insulating target materialincluding oxides of La and Ni and an oxide of Si.

4. EXAMPLES

Examples according to the invention and comparative examples aredescribed below. Note that the invention is not limited to the followingexamples.

4.1. Example 1 and Comparative Example 1

An insulating target according to Example 1 was formed using thefollowing method.

A first powder was produced. In more detail, a powder of an oxide of Laand a powder of an oxide of Ni were mixed at a composition ratio of 1:1.The resulting mixed material was calcined at 900 to 1000° C. and thenpulverized to obtain a first powder.

A second powder was then produced. In more detail, the first powder anda silicon alkoxide solution were mixed. The silicon alkoxide solutionwas prepared by dissolving a silicon alkoxide in an alcohol in an amountof 5 mol %.

The powder and the solution were then separated by filtration to obtaina second powder. The resulting second powder was obtained by mixing thefirst powder and the solution.

The second powder was calcined at 900 to 1000° C. and then pulverized toobtain a third powder.

The third powder was sintered using a known method. In more detail, thethird powder was placed in a die and sintered by vacuum hot pressing.The third powder was sintered at 1400° C. A target sample 1 of Example 1was thus obtained.

FIG. 2 is a photograph of the surface of the target sample 1. As shownin FIG. 2, it was confirmed that the target of Example 1 had a uniformsurface and did not contain defects such as cracks.

Comparative Example 1 is described below. In Comparative Example 1, atarget sample 2 was obtained in the same manner as in Example 1 exceptthat the step of forming the second powder by mixing the first powderand the solution was omitted. Specifically, the target sample 2 ofComparative Example 1 was obtained by directly sintering the firstpowder of Example 1. The surface of the target sample 2 was observed. Asa result, it was confirmed that cracks occurred in the surface of thetarget, as shown in FIG. 3.

4.2. Example 2 and Comparative Example 2

In Example 2, a film of a conductive complex oxide (La,Ni,Si)O₃(hereinafter called “LNSO film 1”) with a thickness of 80 nm was formedon a base by RF sputtering using the target sample 1 obtained inExample 1. As the base, a base formed by stacking a ZrO₂ film, a TiO_(X)film, and a Pt film on a silicon substrate in that order was used. TheRF sputtering was performed at a base temperature of 400° C., a power of1400 W, a base-target distance of 70 mm, and a gas ratio of Ar/O₂=80/20.

The LNSO film 1 was subjected to X-ray analysis, SEM observation, andoutward appearance observation. The results are shown in FIG. 4. FIG. 4shows the results for a sample (AsDepo) immediately after depositing theLNSO film 1, a sample obtained by annealing the deposited LNSO film 1 at700 to 800° C. in an oxygen atmosphere, and a sample obtained byannealing the deposited LNSO film 1 at 700 to 800° C. in an argon ornitrogen atmosphere. FIG. 5 shows the X-ray diffraction patterns of theLNSO film 1. In FIG. 5, the pattern indicated by the symbol “a” is thepattern of the LNSO film 1 immediately after deposition, and the patternindicated by the symbol “b” is the pattern of the LNSO film 1 annealedin an oxygen atmosphere. FIG. 6 is an SEM image of the LNSO film 1annealed in an oxygen atmosphere, and FIG. 7 is a photograph of theoutward appearance of the LNSO film 1.

The following items were confirmed from FIGS. 4 to 7.

As shown in FIG. 5, the LNSO film 1 of Example 2 was (100)-oriented. Thepeak was increased and 20 was increased to some extent due to annealing.As is clear from the SEM image, it was confirmed that the AsDepo LNSOfilm 1 and the annealed LNSO film 1 exhibited excellent surfacemorphology. As is clear from the outward appearance photograph, it wasconfirmed that the AsDepo LNSO film 1 and the annealed LNSO film 1 had auniform surface state.

In Comparative Example 2, an LNSO film 2 was obtained in the same manneras in Example 2 except for using the target sample 2 obtained inComparative Example 1. The LNSO film 2 was subjected to X-ray analysis,SEM observation, and outward appearance observation in the same manneras in Example 2. The results are shown in FIG. 8. FIG. 8 shows theresults for a sample (AsDepo) immediately after depositing the LNSO film2, a sample obtained by annealing the deposited LNSO film 2 at 700 to800° C. in an oxygen atmosphere, and a sample obtained by annealing thedeposited LNSO film 2 at 700 to 800° C. in an argon or nitrogenatmosphere. FIGS. 9 and 10 show the X-ray diffraction patterns of theLNSO film 2. FIG. 9 is the pattern of part of the annealed LNSO film 2,and FIG. 10 is the pattern of another part of the LNSO film 2. FIG. 11is an SEM image of the LNSO film 2 annealed in an oxygen atmosphere, andFIG. 12 is a photograph of the outward appearance of the LNSO film 2.

The following items were confirmed from FIGS. 8 to 12.

As shown in FIG. 12, it was confirmed that the LNSO film 2 ofComparative Example 2 had a nonuniform surface outward appearance, inwhich the color of the surface differs between the upper portion and thelower portion of the photograph. FIG. 9 shows the X-ray pattern of theLNSO film 2 in the upper portion of the outward appearance photograph,and FIG. 10 shows the X-ray pattern of the LNSO film 2 in the lowerportion of the outward appearance photograph. As shown in FIGS. 9 and10, it was confirmed that the LNSO film 2 was (100)-oriented in thelower portion of the outward appearance photograph, and that the LNSOfilm 2 was (100)-oriented to only a small extent in the upper portion ofthe outward appearance photograph. Specifically, it was confirmed thatthe LNSO film 2 of Comparative Example 2 exhibited nonuniformcrystallinity. As is clear from the SEM image, it was confirmed that theannealed LNSO films 2 exhibited poor surface morphology.

4.3. Example 3 and Comparative Example 3

In Example 3, an LNSO film 3 with a thickness of 80 nm was formed on abase in the same manner as in Example 2 except for changing the gasratio during RF sputtering to Ar/O₂=100/0 (atmosphere containing onlyargon).

The LNSO film 3 was subjected to X-ray analysis and SEM observation. Theresults are shown in FIG. 13. FIG. 13 shows the results for a sample(AsDepo) immediately after depositing the LNSO film 3, a sample obtainedby annealing the deposited LNSO film 3 at 700 to 800° C. in an oxygenatmosphere, and a sample obtained by annealing the deposited LNSO film 3at 700 to 800° C. in an argon or nitrogen atmosphere. FIG. 14 shows theX-ray diffraction patterns of the LNSO film 3. In FIG. 14, the patternindicated by the symbol “a” is the pattern of the LNSO film 3immediately after deposition, and the pattern indicated by the symbol“b” is the pattern of the LNSO film 3 annealed in an oxygen atmosphere.

The following items were confirmed from FIGS. 13 and 14.

The LNSO film 3 of Example 3 was (100)-oriented. The peak was increasedand 20 was increased to some extent due to annealing. As is clear fromthe SEM image, it was confirmed that the AsDepo LNSO film 3 and theannealed LNSO film 3 exhibited excellent surface morphology.

In Comparative Example 3, an LNSO film 4 was obtained in the same manneras in Example 3 except for using the target sample 2 obtained inComparative Example 1. The LNSO film 4 was subjected to X-ray analysisand SEM observation in the same manner as in Example 3. FIG. 14 showsthe X-ray diffraction pattern (symbol “c”) of the LNSO film 4 ofComparative Example 3. As shown in FIG. 14, the LNSO film 4 was(100)-oriented to only a small extent, and was (100)-oriented to a smallextent.

From the above results, it was confirmed that an insulating LNSO targetmaterial which does not contain cracks or the like and exhibitsexcellent uniformity can be obtained according to the examples of theinvention. It was also confirmed that the conductive LNSO film depositedusing the insulating LNSO target material exhibited excellent propertiesincluding excellent crystal orientation, surface morphology, anduniformity. It was also confirmed that an excellent conductive LNSO filmcan be obtained using the insulating LNSO target material according tothe examples even in an argon atmosphere which does not contain oxygen.

5. Device

A device according to one embodiment of the invention includes a baseand the conductive complex oxide film according to the invention formedabove the base. The device according to one embodiment of the inventionincludes a part including the conductive complex oxide film according tothe invention and an electronic instrument including the part. Examplesof the device according to the invention are described below.

5.1. Semiconductor Device

A semiconductor device including the conductive complex oxide filmaccording to the invention is described below. This embodimentillustrates an example of a ferroelectric memory device including aferroelectric capacitor which is an example of the semiconductor device.

FIGS. 15A and 15B are views schematically showing a ferroelectric memorydevice 1000 in which the conductive complex oxide film according to theinvention is used as an electrode. FIG. 15A shows the planar shape ofthe ferroelectric memory device 1000, and FIG. 15B shows the crosssection along the line I-I in FIG. 15A.

As shown in FIG. 15A, the ferroelectric memory device 1000 includes amemory cell array 200 and a peripheral circuit section 300. The memorycell array 200 and the peripheral circuit section 300 are formed indifferent layers. The peripheral circuit section 300 is disposed on asemiconductor substrate 400 in a region differing from the memory cellarray 200. As specific examples of the peripheral circuit section 300, aY gate, sense amplifier, input/output buffer, X address decoder, Yaddress decoder, or address buffer can be given.

In the memory cell array 200, row-select lower electrodes 210(wordlines) and column-select upper electrodes 220 (bitlines) arearranged to intersect. The lower electrodes 210 and the upper electrodes220 are formed in the shape of stripes formed of linear signalelectrodes. The signal electrodes may be formed so that the lowerelectrode 210 serves as the bitline and the upper electrode 220 servesas the wordline.

As shown in FIG. 15B, a ferroelectric film 215 is disposed between thelower electrodes 210 and the upper electrodes 220. In the memory cellarray 200, a memory cell which functions as a ferroelectric capacitor230 is formed in the region in which the lower electrode 210 and theupper electrode 220 intersect. At least either the lower electrode 210or the upper electrode 220 is a film formed using the conductive complexoxide film according to the invention. The lower electrode 210 and theupper electrode 220 may be single layers of the conductive complex oxidefilm according to the invention, or may have a stacked structureincluding the conductive complex oxide film according to the inventionand another conductive film. A known barrier film may be formed betweena first interlayer dielectric 420 and the lower electrode 210. Theferroelectric film 215 may be disposed between the lower electrode 210and the upper electrode 220 at least in the region in which the lowerelectrode 210 and the upper electrode 220 intersect.

In the ferroelectric memory device 1000, a second interlayer dielectric430 is formed to cover the lower electrode 210, the ferroelectric film215, and the upper electrode 220. An insulating protective layer 440 isformed on the second interlayer dielectric 430 so that interconnectlayers 450 and 460 are covered with the protective layer 440.

As shown in FIG. 15A, the peripheral circuit section 300 includesvarious circuits for selectively writing or reading information into orfrom the memory cell array 200. For example, the peripheral circuitsection 300 includes a first driver circuit 310 for selectivelycontrolling the lower electrode 210, a second driver circuit 320 forselectively controlling the upper electrode 220, and a signal detectioncircuit (not shown) such as a sense amplifier.

As shown in FIG. 15B, the peripheral circuit section 300 includes a MOStransistor 330 formed on the semiconductor substrate 400. The MOStransistor 330 includes a gate insulating film 332, a gate electrode334, and source/drain regions 336. The MOS transistors 330 are isolatedby an element isolation region 410. The first interlayer dielectric 420is formed on the semiconductor substrate 400 on which the MOS transistor330 is formed. The peripheral circuit section 300 is electricallyconnected with the memory cell array 200 through an interconnect layer51.

An example of write and read operations of the ferroelectric memorydevice 1000 is described below.

In the read operation, a read voltage is applied to the capacitor in theselected memory cell. This also serves as the write operation of “0”. Atthis time, a current flowing through the selected bitline or a potentialwhen causing the bitline to be in a high impedance state is read byusing a sense amplifier. A specific voltage is applied to the capacitorsof the unselected memory cells in order to prevent occurrence ofcrosstalk during reading.

In the write operation of “1”, a write voltage which causes apolarization reversal is applied to the capacitor in the selected memorycell. In the write operation of “0”, a write voltage which does notcause a polarization reversal is applied to the capacitor in theselected memory cell to hold the “0” state written during the readoperation. A specific voltage is applied to the capacitors in theunselected memory cells in order to prevent occurrence of crosstalkduring writing.

In the ferroelectric memory device 1000, the ferroelectric capacitor 230includes the ferroelectric film 215 which can be crystallized at a lowtemperature. Therefore, the ferroelectric memory device 1000 can bemanufactured without causing deterioration of the MOS transistor 330making up the peripheral circuit section 300 and the like. Since theferroelectric capacitor 230 has excellent hysteresis characteristics, ahighly reliable ferroelectric memory device 1000 can be provided.

FIG. 16 is a structural diagram of a ITIC ferroelectric memory device500 as another example of the semiconductor device. FIG. 17 is anequivalent circuit diagram of the ferroelectric memory device 500.

As shown in FIG. 16, the ferroelectric memory device 500 is a memorydevice having a structure similar to that of a DRAM, and includes acapacitor 504 (1C) including a lower electrode 501, an upper electrode502 connected with a plate line, and a ferroelectric film 503 accordingto the above-described embodiment, and a switch transistor element 507(1T) including source/drain electrodes, one of which is connected with adata line 505, and a gate electrode 506 connected with a wordline. Inthis example, at least either the lower electrode 501 or the upperelectrode 502 is a film formed using the conductive complex oxide filmaccording to the invention in the same manner as in the example shown inFIGS. 15A and 15B. In the 1T1C memory, data can be written and read at aspeed as high as 100 ns or less, and the written data does notvolatilize. Therefore, the 1T1C memory is a promising memory which mayreplace an SRAM or the like.

The semiconductor device according to this embodiment is not limited tothe above-described semiconductor devices. The semiconductor deviceaccording to this embodiment may also be applied to a 2T2C ferroelectricmemory device and the like.

5.2. Piezoelectric Device

An example in which the conductive complex oxide film according to theinvention is applied to a piezoelectric device is described below.

FIG. 18 is a cross-sectional view showing a piezoelectric device 1including the conductive complex oxide film according to the invention.The piezoelectric device 1 includes a substrate 2, a lower electrode 3formed on the substrate 2, a piezoelectric film 4 formed on the lowerelectrode 3, and an upper electrode 5 formed on the piezoelectric film4. At least either the lower electrode 3 or the upper electrode 5 is afilm formed using the conductive complex oxide film according to theinvention. The lower electrode 3 and the upper electrode 5 may be singlelayers of the conductive complex oxide film according to the invention,or may have a stacked structure including the conductive complex oxidefilm according to the invention and another conductive film.

As the substrate 2, a silicon substrate may be used. In this embodiment,a (110)-oriented single crystal silicon substrate is used as thesubstrate 2. A (100)-oriented single crystal silicon substrate or a(111)-oriented single crystal silicon substrate may also be used as thesubstrate 2. In addition, a substrate obtained by forming an amorphoussilicon oxide film such as a thermal oxide film or a natural oxide filmon the surface of a silicon substrate may also be used as the substrate2. The substrate 2 is processed so that ink cavities 521 are formed inan inkjet recording head 50 as described later (see FIG. 19).

The lower electrode 3 is an electrode for applying a voltage to thepiezoelectric film 4. The lower electrode 3 may be formed to have thesame planar shape as the piezoelectric film 4, for example. When two ormore piezoelectric devices 1 are formed in the inkjet recording head 50described later (see FIG. 19), the lower electrode 3 may be formed tofunction as a common electrode for the piezoelectric devices 1. Thelower electrode 3 is formed to have a thickness of about 100 to 200 nm,for example.

5.3. Inkjet Recording Head

An inkjet recording head in which the above-described piezoelectricdevice functions as a piezoelectric actuator, and an inkjet printerincluding the inkjet recording head are described below. FIG. 19 is aside cross-sectional view showing a schematic configuration of theinkjet recording head according to this embodiment, and FIG. 20 is anexploded perspective view of the inkjet recording head which isillustrated in a vertically reversed state. FIG. 21 shows an inkjetprinter 700 including the inkjet recording head according to thisembodiment.

As shown in FIG. 19, the inkjet recording head 50 includes a head body(base) 57 and a piezoelectric section 54 formed over the head body 57.The piezoelectric device 1 shown in FIG. 18 is provided in thepiezoelectric section 54. The piezoelectric device 1 is formed bystacking the lower electrode 3, the piezoelectric film (ferroelectricfilm) 4, and the upper electrode 5 in that order. In the inkjetrecording head, the piezoelectric section 54 functions as apiezoelectric actuator.

The inkjet recording head 50 includes a nozzle plate 51, an ink chambersubstrate 52, an elastic film 55, and the piezoelectric section 54bonded to the elastic film 55. These components are accommodated in ahousing 56. The inkjet recording head 50 forms an on-demand type piezojet head.

The nozzle plate 51 is formed of a stainless steel rolled plate or thelike, in which a number of nozzles 511 for discharging ink droplets areformed in a row. The pitch between the nozzles 511 is appropriatelydetermined depending on the printing precision.

The ink chamber substrate 52 is attached to (secured on) the nozzleplate 51. In the ink chamber substrate 52, cavities (ink cavities) 521,a reservoir 523, and supply ports 524 are partitioned by the nozzleplate 51, a side wall (partition wall) 522, and the elastic film 55. Thereservoir 523 temporarily stores ink supplied from an ink cartridge (notshown). The ink is supplied to each cavity 521 from the reservoir 523through the supply ports 524.

As shown in FIGS. 19 and 20, the cavity 521 is disposed corresponding tothe nozzle 511. The volume of the cavity 521 can be changed by vibrationof the elastic film 55. The cavity 521 is configured to discharge theink as a result of a change in volume.

A (110)-oriented single crystal silicon substrate is used as the basematerial for the ink chamber substrate 52. Since the (110)-orientedsingle crystal silicon substrate is suitable for anisotropic etching,the ink chamber substrate 52 can be easily and reliably formed. Thesingle crystal silicon substrate is used so that the surface on whichthe elastic film 55 is formed is the (110) plane.

The elastic film 55 is disposed on the ink chamber substrate 52 on theside opposite to the nozzle plate 51. The piezoelectric sections 54 aredisposed on the elastic film 55 on the side opposite to the ink chambersubstrate 52. As shown in FIG. 20, a communication hole 531 is formedthrough the elastic film 55 in the thickness direction at a specificposition of the elastic film 55. The ink is supplied to the reservoir523 from the ink cartridge through the communication hole 531.

The piezoelectric section is electrically connected with a piezoelectricdevice driver circuit (not shown) and is actuated (vibrate or deformed)based on a signal from the piezoelectric device driver circuit.Specifically, the piezoelectric section 54 functions as a vibrationsource (head actuator). The elastic film 55 vibrates due to vibration(deflection) of the piezoelectric section 54, and functions tomomentarily increase the pressure inside the cavity 521.

An example of the inkjet recording head which discharges ink isdescribed above. However, this embodiment aims at a liquid jet headusing a piezoelectric device and a liquid jet device in general. As theliquid jet head, a recording head used for an image recording devicesuch as a printer, a color material jet head used to manufacture a colorfilter for a liquid crystal display or the like, an electrode materialjet head used to form an electrode of an organic EL display, a fieldemission display (FED), or the like, a bio-organic substance jet headused to manufacture a bio-chip, and the like can be given.

5.4. Surface Acoustic Wave Device

An example of a surface acoustic wave device to which the conductivecomplex oxide film according to the invention is applied is describedbelow with reference to the drawings. FIG. 22 is a cross-sectional viewschematically showing a surface acoustic wave device 300 according tothis embodiment.

The surface acoustic wave device 300 includes a substrate 11, apiezoelectric film 12 formed on the substrate 11, and interdigitaltransducers (hereinafter called “IDT electrodes”) 18 and 19 formed onthe piezoelectric film 12. The IDT electrodes 18 and 19 have a specificpattern. The IDT electrodes 18 and 19 are formed using the conductivecomplex oxide film according to the invention.

The surface acoustic wave device 300 according to this embodiment isformed as described below using the conductive complex oxide filmaccording to the invention, for example.

The conductive complex oxide film according to the invention is formedon the piezoelectric film 12 shown in FIG. 22 by RF sputtering using theinsulating target material according to the invention. The IDTelectrodes 18 and 19 are formed on the piezoelectric film 12 bypatterning the conductive complex oxide film using a known lithographytechnology and etching technology.

5.5 Frequency Filter

An example of a frequency filter to which the conductive complex oxidefilm according to the invention is applied is described below withreference to the drawings. FIG. 23 is a view schematically showing thefrequency filter according to this embodiment.

As shown in FIG. 23, the frequency filter includes a base 140. As thebase 140, a laminate similar to that of the above-described surfaceacoustic wave device 300 may be used (see FIG. 22).

IDT electrodes 141 and 142 are formed on the upper side of the base 140.Sound absorbing sections 143 and 144 are formed on the upper side of thebase 140 so that the IDT electrodes 141 and 142 are positioned betweenthe sound absorbing sections 143 and 144. The sound absorbing sections143 and 144 absorb surface acoustic waves propagated on the surface ofthe base 140. A high-frequency signal source 145 is connected with theIDT electrode 141, and signal lines are connected with the IDT electrode142. The IDT electrodes 141 and 142 may be formed using the conductivecomplex oxide film according to the invention.

The operation of the frequency filter is described below.

In the above-described configuration, when a high-frequency signal isoutput from the high-frequency signal source 145, the high-frequencysignal is applied to the IDT electrode 141, whereby surface acousticwaves occur on the upper side of the base 140. The surface acousticwaves propagated from the IDT electrode 141 toward the sound absorbingsection 143 are absorbed by the sound absorbing section 143. However,the surface acoustic waves propagated toward the IDT electrode 142 andhaving a specific frequency determined by the pitch of the IDT electrode142 or the like or having a frequency in a specific band are convertedinto electric signals, and supplied to terminals 146 a and 146 b throughthe signal lines. Most of the frequency components other than thespecific frequency or the frequency in the specific band are absorbed bythe sound absorbing section 144 through the IDT electrode 142.Therefore, it is possible to obtain (filter) only surface acoustic waveshaving the specific frequency or the frequency in the specific band fromthe electric signals supplied to the IDT electrode 141 of the frequencyfilter according to this embodiment.

5.6. Oscillator

An example of an oscillator to which the conductive complex oxide filmaccording to the invention is applied is described below with referenceto the drawings. FIG. 24 is a view schematically showing the oscillatoraccording to this embodiment.

As shown in FIG. 24, the oscillator includes a base 150. As the base150, a laminate (see FIG. 22) similar to that of the above-describedsurface acoustic wave device 300 may be used.

An IDT electrode 151 is formed on the upper side of the base 150, andIDT electrodes 152 and 153 are formed so that the IDT electrode 151 ispositioned between the IDT electrodes 152 and 153. A high-frequencysignal source 154 is connected with a comb-shaped electrode 151 aforming the IDT electrode 151, and a signal line is connected with theother comb-shaped electrode 151 b. The IDT electrode 151 corresponds toan electrode for applying an electric signal, and the IDT electrodes 152and 153 correspond to electrodes for causing a specific frequencycomponent or a frequency component in a specific band of surfaceacoustic waves generated by the IDT electrode 151 to resonate. The IDTelectrodes 151, 152, and 153 may be formed using the conductive complexoxide film according to the invention.

The operation of the oscillator is described below.

In the above-described configuration, when a high-frequency signal isoutput from the high-frequency signal source 154, the high-frequencysignal is applied to the comb-shaped electrode 151 a of the IDTelectrode 151, whereby surface acoustic waves propagated toward the IDTelectrode 152 and surface acoustic waves propagated toward the IDTelectrode 153 are generated on the upper side of the base 150. Thesurface acoustic waves having a specific frequency component arereflected by the IDT electrodes 152 and 153 so that stationary wavesoccur between the IDT electrodes 152 and 153. The surface acoustic waveshaving a specific frequency component are repeatedly reflected by theIDT electrodes 152 and 153, whereby a specific frequency component or afrequency component in a specific band resonates to increase theamplitude. A part of the surface acoustic waves having the specificfrequency component or the frequency component in the specific band isremoved through the comb-shaped electrode 151 b of the IDT electrode151, whereby electric signals having a frequency corresponding to theresonant frequency of the IDT electrodes 152 and 153 (or frequencyhaving a certain band) can be supplied to terminals 155 a and 155 b.

FIGS. 25 and 26 are views schematically showing an example in which theabove-described oscillator is applied to a voltage controlled SAWoscillator (VCSO). FIG. 25 is a side perspective view, and FIG. 26 is atop perspective view.

The VCSO is provided in a housing 60 made of a metal (aluminum orstainless steel). An integrated circuit (IC) 62 and an oscillator 63 areprovided on a substrate 61. In this case, the IC 62 is an oscillatingcircuit which controls the frequency applied to the oscillator 63corresponding to the voltage value input from an external circuit (notshown).

In the oscillator 63, IDT electrodes 65 a to 65 c are formed on a base64. The configuration of the oscillator 63 is substantially the same asthe configuration of the oscillator shown in FIG. 24. As the base 64, alaminate similar to that of the oscillator shown in FIG. 24 may be used.The IDT electrodes 65 a to 65 c may be formed using the conductivecomplex oxide film according to the invention.

An interconnect 66 for electrically connecting the IC 62 with theoscillator 63 is patterned on the substrate 61. The IC 62 and theinterconnect 66 are connected through a wire 67 such as a gold wire, andthe oscillator 63 and the interconnect 66 are connected through a wire68 such as a gold wire. This allows the IC 62 and the oscillator 63 tobe electrically connected through the interconnect 66.

The VCSO shown in FIGS. 25 and 26 is used as a voltage controlledoscillator (VCO) of a PLL circuit shown in FIG. 27, for example. FIG. 27is a block diagram showing a basic configuration of the PLL circuit. ThePLL circuit includes a phase comparator 71, a low-pass filter 72, anamplifier 73, and a VCO 74. The phase comparator 71 compares the phase(or frequency) of a signal input through an input terminal 70 with thephase (or frequency) of a signal output from the VCO 74, and generatesan error voltage signal of which the value is set corresponding to thedifference. The low-pass filter 72 allows only a low-frequency componentat a position of the error voltage signal output from the phasecomparator 71 to pass therethrough. The amplifier 73 amplifies thesignal output from the low-pass filter 72. The VCO 74 is an oscillatingcircuit of which the oscillation frequency continuously changes within acertain range corresponding to the input voltage value.

The PLL circuit having such a configuration operates so that thedifference between the phase (or frequency) of the signal input throughthe input terminal 70 and the phase (or frequency) of the signal outputfrom the VCO 74 is decreased, and synchronizes the frequency of thesignal output from the VCO 74 with the frequency of the signal inputthrough the input terminal 70. When the frequency of the signal outputfrom the VCO 74 has been synchronized with the frequency of the signalinput through the input terminal 70, the PLL circuit outputs a signalwhich coincides with the signal input through the input terminal 70excluding a specific phase difference and follows a change in the inputsignal.

As described above, the frequency filter and the oscillator according tothis embodiment include the surface acoustic wave device according tothe invention having a high electromechanical coupling factor.Therefore, this embodiment allows a reduction in the size of thefrequency filter and the oscillator.

5.7. First Electronic Instrument

A first example of an electronic circuit and an electronic instrument towhich the invention is applied is described below with reference to thedrawings. FIG. 28 is a block diagram showing the electricalconfiguration of an electronic instrument according to this embodiment.The electronic instrument is a portable telephone, for example.

An electronic instrument 300 includes an electronic circuit 310, atransmitter 80, a receiver 91, an input section 94, a display section95, and an antenna section 86. The electronic circuit 310 includes atransmission signal processing circuit 81, a transmission mixer 82, atransmission filter 83, a transmission power amplifier 84, atransmission and reception branching filter 85, a low-noise amplifier87, a reception filter 88, a reception mixer 89, a reception signalprocessing circuit 90, a frequency synthesizer 92, and a control circuit93.

In the electronic circuit 310, the frequency filter shown in FIG. 23 maybe used as the transmission filter 83 and the reception filter 88. Thefrequency to be filtered (frequency allowed to pass) is individually setfor the transmission filter 83 and the reception filter 88 correspondingto the necessary frequency of the signal output from the transmissionmixer 82 and the frequency necessary for the reception mixer 89. As theVCO 74 of the PLL circuit (see FIG. 27) provided in the frequencysynthesizer 92, the oscillator shown in FIG. 24 or the VCSO shown inFIGS. 25 and 26 may be used.

The transmitter 80 is realized by a microphone which converts a soundwave signal into an electric signal, for example. The transmissionsignal processing circuit 81 is a circuit which performs processing suchas D/A conversion or modulation for an electric signal output from thetransmitter 80. The transmission mixer 82 mixes the signal output fromthe transmission signal processing circuit 81 by using the signal outputfrom the frequency synthesizer 92. The transmission filter 83 allowsonly a signal having a frequency for which an intermediate frequency(hereinafter abbreviated as “IF”) is necessary to pass therethrough, andremoves a signal having an unnecessary frequency. The signal output fromthe transmission filter 83 is converted into an RF signal by aconversion circuit (not shown). The transmission power amplifier 84amplifies electric power of the RF signal output from the transmissionfilter 83, and outputs it to the transmission and reception branchingfilter 85.

The transmission and reception branching filter 85 outputs the RF signaloutput from the transmission power amplifier 84 to the antenna section86, and transmits the RF signal from the antenna section 86 as radiowaves. The transmission and reception branching filter 85 branches asignal received by the antenna section 86, and outputs the resultingsignal to the low-noise amplifier 87. The low-noise amplifier 87amplifies the signal received from the transmission and receptionbranching filter 85. The signal output from the low-noise amplifier 87is converted into an IF by a conversion circuit (not shown).

The reception filter 88 allows only a signal having a frequency forwhich an IF converted by the conversion circuit (not shown) is necessaryto pass therethrough, and removes a signal having an necessaryfrequency. The reception mixer 89 mixes the signal output from thereception filter 88 by using the signal output from the frequencysynthesizer 92. The reception signal processing circuit 90 is a circuitwhich performs processing such as A/D conversion or demodulation for thesignal output from the reception mixer 89. The receiver 91 is realizedby a small speaker which converts electric signals into sound waves, forexample.

The frequency synthesizer 92 is a circuit which generates a signalsupplied to the transmission mixer 82 and a signal supplied to thereception mixer 89. The frequency synthesizer 92 includes a PLL circuit,and generates a signal by dividing the frequency of a signal output fromthe PLL circuit. The control circuit 93 controls the transmission signalprocessing circuit 81, the reception signal processing circuit 90, thefrequency synthesizer 92, the input section 94, and the display section95. The display section 95 displays the state of the instrument to theuser of the portable telephone, for example. The input section 94 allowsthe user of the portable telephone to input instructions, for example.

5.8. Second Electronic Instrument

A second example of an electronic circuit and an electronic instrumentto which the invention is applied is described below with reference tothe drawings. In this embodiment, a reader/writer 2000 and acommunication system 3000 using the reader/writer 2000 are described asan example of the electronic instrument. FIG. 29 is a view showing thecommunication system 3000 using the reader/writer 2000 according to thisembodiment, and FIG. 30 is a schematic block diagram of thecommunication system 3000 shown in FIG. 29.

As shown in FIG. 29, the communication system 3000 includes thereader/writer 2000 and a contactless information medium 2200. Thereader/writer 2000 transmits or receives radio waves W (hereinafter maybe called “carrier”) having a carrier frequency f_(c) to or from thecontactless information medium 2200, and communicates with thecontactless information medium 2200 using wireless communication. Thecarrier frequency f_(c) of the radio wave W may be a carrier frequencyin an arbitrary frequency band. As shown in FIGS. 29 and 30, thereader/writer 2000 includes a main body 2105, an antenna section 2110positioned on the upper side of the main body 2105, a control interfacesection 2120 provided in the main body 2105, and a power supply circuit172. The antenna section 2110 and the control interface section 2120 areelectrically connected through a cable 2180. The reader/writer 2000 isconnected with an external host device (e.g. processing device) throughthe control interface section 2120 (not shown).

The antenna section 2110 has the function of transmitting and receivinginformation to and from the contactless information medium 2200. Asshown in FIG. 29, the antenna section 2110 has a specific communicationarea (area indicated by the dotted line). The antenna section 2110includes a loop antenna 112 and a matching circuit 114.

The control interface section 2120 includes a transmission section 161,a damped oscillation cancellation section (hereinafter called“cancellation section”) 140, a reception section 168, and a controller160.

The transmission section 161 modulates data transmitted from an externaldevice (not shown), and transmits the modulated data to the loop antenna112. The transmission section 161 includes an oscillation circuit 162, amodulation circuit 163, and a driver circuit 164. The oscillationcircuit 162 is a circuit for generating a carrier having a specificfrequency. The oscillation circuit 162 is generally formed using aquartz oscillator or the like. The communication frequency and thedetection sensitivity can be increased by using the oscillator accordingto the invention. The modulation circuit 163 is a circuit whichmodulates the carrier according to information provided. The drivercircuit 164 receives the modulated carrier and amplifies electric powerto drive the antenna section 2110.

The cancellation section 165 has the function of reducing the dampedoscillation caused by the loop antenna 112 of the antenna section 2110along with turning the carrier ON/OFF. The cancellation section 165includes a logic circuit 166 and a cancellation circuit 167.

The reception section 168 includes a detection section 169 and ademodulator circuit 170. The reception section 168 restores a signaltransmitted from the contactless information medium 2200. The detectionsection 169 detects a change in current which flows through the loopantenna 112, for example. The demodulator circuit 170 is a circuit whichdemodulates the change detected by the detection section 169.

The controller 160 acquires information from the demodulated signal andtransfers the information to the external device. The power supplycircuit 172 receives power from the outside, arbitrarily performsvoltage conversion, and supplies necessary power to each circuit. Abuilt-in cell may be used as the power supply.

The contactless information medium 2200 communicates with thereader/writer 2000 using electromagnetic waves (radio waves). Asexamples of the contactless information medium 2200, a contactless ICtag, a contactless IC card, and the like can be given.

The operation of the communication system 3000 using the reader/writer2000 according to this embodiment is described below. When data istransferred to the contactless information medium 2200 from thereader/writer 2000, data from the external device (not shown) isprocessed by the controller 160 of the reader/writer 2000, andtransmitted to the transmission section 161. In the transmission section161, a high-frequency signal having a specific amplitude is supplied asthe carrier from the oscillation circuit 162. The carrier is modulatedby the modulation circuit 163 so that the modulated high-frequencysignal is output. The modulated high-frequency signal output from themodulation circuit 163 is supplied to the antenna section 2110 throughthe driver circuit 164. The cancellation section 165 generates aspecific pulse signal in synchronization with the OFF timing of themodulated high-frequency signal to contribute to a reduction in thedamped oscillation in the loop antenna 112.

In the contactless information medium 2200, the modulated high-frequencysignal is supplied to the receiver circuit 180 through the antennasection 186. The modulated high-frequency signal is also supplied to thepower supply circuit 182 so that a specific power supply voltagenecessary for each section of the contactless information medium 2200 isgenerated. The data output from the receiver circuit 180 is demodulatedand supplied to the logic control circuit 184. The logic control circuit184 operates based on the output from a clock 183. The logic controlcircuit 184 processes the supplied data and writes specific data into amemory 185.

When data is transferred to the reader/writer 2000 from the contactlessinformation medium 2200, an unmodulated high-frequency signal having aspecific amplitude is output from the modulation circuit 163 of thereader/writer 2000. The high-frequency signal is transferred to thecontactless information medium 2200 through the driver circuit 164 andthe loop antenna 112 of the antenna section 2110.

In the contactless information medium 2200, the data read from thememory 185 is processed by the logic control circuit 184 and supplied tothe transmission circuit 181. In the transmission circuit 181, theswitch is turned ON/OFF depending on the “1” or “0” bit of the data.

In the reader/writer 2000, the load of the loop antenna 112 of theantenna section 2110 changes when the switch of the transmission circuit181 is turned ON/OFF. Therefore, the amplitude of the high frequencycurrent which flows through the loop antenna 112 changes. Specifically,the amplitude of the high frequency current is modulated by the datasupplied from the contactless information medium 2200. The highfrequency current is detected by the detection section 169 of thereception section 168 and demodulated by the demodulator circuit 170 toobtain data. The data is processed by the controller 160 and transmittedto the external device or the like.

Although only some embodiments of the invention have been described indetail above, those skilled in the art would readily appreciate thatmany modifications are possible in the embodiments without materiallydeparting from the novel teachings and advantages of the invention. Forexample, the frequency filter and the oscillator according to theinvention may be respectively applied to a broadband filter and a VCO ina UWB system, portable telephone, wireless LAN, and the like.

In the above-described embodiments, the communication system using theportable telephone and the reader/writer is described as an example ofthe device, and the electronic circuit provided in the portabletelephone and the reader/writer is described as an example of theelectronic circuit. However, the invention is not limited thereto. Theinvention may be applied to various mobile communication instruments andelectronic circuits provided therein. For example, the invention mayalso be applied to communication instruments used in a stationary statesuch as a tuner which receives broadcast satellite (BS) broadcasts andelectronic circuits provided therein, and devices such as a HUB using anoptical signal propagated through an optical cable and electroniccircuits provided therein.

The invention is not limited to the above-described embodiments, andvarious modifications can be made. For example, the invention includesvarious other configurations substantially the same as theconfigurations described in the embodiments (in function, method andresult, or in objective and result, for example). The invention alsoincludes a configuration in which an unsubstantial portion in thedescribed embodiments is replaced. The invention also includes aconfiguration having the same effects as the configurations described inthe embodiments, or a configuration able to achieve the same objective.Further, the invention includes a configuration in which a publiclyknown technique is added to the configurations in the embodiments.

Although only some embodiments of the invention have been described indetail above, those skilled in the art will readily appreciate that manymodifications are possible in the embodiments without departing from thenovel teachings and advantages of this invention. Accordingly, all suchmodifications are intended to be included within the scope of thisinvention.

1. An insulating target material for obtaining a conductive complexoxide film represented by a general formula ABO₃, the insulating targetmaterial comprising: an oxide of an element A; an oxide of an element B;and at least one of an Si compound and a Ge compound.
 2. The insulatingtarget material as defined in claim 1, wherein the element A is at leastone element selected from La, Ca, Sr, Mn, Ba, and Re.
 3. The insulatingtarget material as defined in claim 1, wherein the element B is at leastone element selected from Ti, V, Sr, Cr, Fe, Co, Ni, Cu, Ru, Ir, Pb, andNd.
 4. The insulating target material as defined in claim 1, wherein theSi compound and the Ge compound are oxides.
 5. The insulating targetmaterial as defined in claim 1, further comprising an Nb compound. 6.The insulating target material as defined in claim 1, wherein theelement A is La, and the element B is Ni.
 7. A method of manufacturingan insulating target material for obtaining a conductive complex oxidefilm represented by a general formula ABO₃, the method comprising:mixing an oxide of an element A and an oxide of an element B,heat-treating the resulting mixed powder, and pulverizing the resultingproduct to obtain a first powder; mixing the first powder and a solutionincluding at least one of an Si raw material and a Ge raw material, andcollecting the resulting powder to obtain a second powder; heat-treatingthe second powder and pulverizing the resulting product to obtain athird powder; and heat-treating the third powder.
 8. The method ofmanufacturing an insulating target material as defined in claim 7,wherein the solution includes at least one of the Si raw material andthe Ge raw material in an amount of 2 to 10 mol %.
 9. The method ofmanufacturing an insulating target material as defined in claim 7,wherein the mixed powder is heat-treated at 900 to 1000° C.
 10. Themethod of manufacturing an insulating target material as defined inclaim 7, wherein the second powder is heat-treated at 900 to 1000° C.11. The method of manufacturing an insulating target material as definedin claim 7, wherein the third powder is heat-treated at 1000 to 1500° C.12. A conductive complex oxide film, being formed by RF sputteringmethod using the insulating target material as defined in claim
 1. 13.An insulating target material, comprising: an oxide of a first element;an oxide of a second element; and at least one of an Si compound and aGe compound.